A single-subject, time-series design was used to describe a female with young-onset Parkinson's disease who, after a period of 15 years, was demonstrating long term side effects of medication in addition to the progression of Parkinson's disease. She underwent a bilateral pallidotomy to address these problems. Prior to her surgery, her spatiotemporal gait kinematics were measured at intervals before and after medication ingestion. The identical procedures were undertaken one month and at four months post-pallidotomy. In all three sessions, the Webster Scale scored her symptoms while her medication was not working (Off) and again when effective (On). After surgery, she was interviewed to obtain a qualitative impression of the outcome. Before the surgery, the gait parameters demonstrated a fluctuating profile. Forty-five minutes post-medication, her gait parameters approached normal levels but significant dyskinetic movements were evident. Her Webster Scale scores indicated advanced Parkinson's disease particularly when Off One-month post-pallidotomy, her gait parameters were more consistent with dyskinesias mildly present. Her Webster Scale scores were reduced while both Off and On. Four months post-pallidotomy her gait parameters were entirely consistent and within normal limits. Her Webster Scale scores were the same Off and On and no dyskinesias were detectable. The excellent result was probably enhanced by the patient's dedication to regular exercise designed to minimize secondary physical complications.